The investigators have successfully depolymerized and fractionated commercial heparins into low molecular weight products with retention of appreciable anticoagulant and lipemic activity. Controlled enzymatic and free radical depolymerization methods have yielded compounds with a spectrum of biological activities and molecular weights and similar chemical structure. Although synthetic, orally effective anticoagulants are available, the importance of the parentally administered heparin in anticoagulant therapy remains unchallenged. An orally active compound with the desirable attributes of heparin could find wide use clinically. Preliminary published studies in mice have demonstrated significant oral absorption of these preparations. In-situ studies of the absorption of a homologous series of heparin derivatives also in the presence of enhancers will be explored. Evidence of transport across intestinal and buccal membranes in intact animals will be detected by both chemical (14C label) and by evidence of anticoagulant and antilipemic activity. This study will provide structural information about heparin molecule, its ability to cross biological membranes in-situ and its potential as an orally active clinically useful anticoagulant.